The investment casting (IC) process is a technique used to produce high-precision metal castings, including complex shapes and metals that are difficult to cast using conventional methods. Typically, the process begins by creating a wax pattern from a mold in the initial steps. The molds used for IC are fabricated using conventional machining techniques. However, this mold preparation approach can be challenging when it comes to fabricating complex shapes and thin walls, particularly in small-batch production scenarios. To overcome this limitation, this study explores a flexible design approach that utilizes three-dimensional printing (3DP) to fabricate IC molds. The key advantage of this approach is the combination of the flexible design mold and the surface roughness (SR) of the casted parts. The experimental results demonstrate that the SR of the casted products fabricated using the 3DP mold is comparable to that obtained from the conventional mold-making process. These findings provide an alternative strategy for preparing IC molds with high flexibility, which can accommodate various scales of production. The 3DP-based approach offers a more adaptable solution compared to conventional machining methods, particularly for complex geometries and small-batch manufacturing.